The petroleum industry is increasingly turning to heavy oil feeds such as heavy crudes, resids, coals, tar sands, etc., as sources for feedstocks. These feedstocks are characterized by high concentrations of asphaltenes rich residues, and low API gravities, with some being as low as less than 0° API.
U.S. Pat. Nos. 7,390,398, 7,431,822, 7,431,823, and 7,431,831 describe processes, systems, and catalysts for processing heavy oil feeds. In various embodiments in the prior art, spent slurry catalyst and unconverted heavy oil feeds are recycled back to the process and combined with fresh heavy oil feeds, thus maximizing heavy oil conversion.
There is still a need for improved systems and methods to upgrade/treat process heavy oil feeds, particularly improved systems for better raw material utilization with less catalyst usage.